Thermoplastic resins are characterized by their many advantageous properties which include optical clarity, high ductility, high heat deflection temperature as well as dimensional stability. As a result of such properties, they are often employed in many commercial applications.
While thermoplastic resins possess the above-described advantageous properties, they often display low abrasion and chemical solvent resistances, and like many other organic polymeric materials, they are susceptible to photodegradation by ultraviolet light. The photodegradation typically results in unfavorable characteristics including yellowing and erosion of the polymer surface.
It is of increasing interest to prepare thermoplastic resins; particularly polycarbonates, that are resistant to abrasion and photodegradation. Such preparation conventionally employs treating the polycarbonate surface with a coating material (silicone hardcoat matrix), whereby the coating material typically contains ultraviolet light absorbing agents such as benzophenone and benzotriazole derivatives.
It is often discovered, however, that the ultraviolet light absorbing agents, themselves, decompose upon exposure to ultraviolet light. This invariably causes microcracks to form in the coating material and leads to a degradation of the favorable properties of the polycarbonate which the agents are originally employed to protect.
The instant invention, therefore, is directed to novel silylated agents capable of absorbing ultraviolet light. Said silylated agents are 4,6-dibenzoyl-2-(trialkoxysilylalkyl) resorcinols which display improved photostability as well as compatibility in silicone hardcoat matrices.